The overall objective of this project is to explore in detail the processes involved in the expression of tissue specific functions by liver cells. The results will be interpreted to further understand normal liver development and function and to elucidate changes resulting from hepatocarcinoma. The cell line Hepa, derived from the mouse hepatoma BW 7756 (Jackson Laboratory), secretes albumin, alpha-fetoprotein and transferrin into the culture medium. The synthesis of these proteins is related to the phase and duration of the cell cycle and to culture conditions not affecting growth. Two basic parameters govern the cellular rate of protein synthesis: 1) the translation rate and 2) cellular number of translation sites. These two parameters and polyribosome size will be evaluated for albumin, alpha-fetoprotein, and transferrin synthesis under various growth conditions and in synchronous cells.